Regulates endothelial cell proliferation and penile vascular remodellingInfluences intracavernosal pressure and tissue remodelling; modulation of the eNOS pathway is critical for vascular restoration in EDThe −2578A allele is associated with increased ED prevalence and severity, notably in metabolic syndromePromoter haplotypes (−1154AA, −2578AA) linked with poorer PDE5I responsiveness. The gene discussed is NOS3; the disease is metabolic process.